1. Field of the Invention
The present invention relates generally to optical imaging systems and, more particularly, to a system and method for transmitting entire images over a single filament of a fiber optic cable.
2. Background of the Invention
It has been known since the late 1920s that light can be transmitted through transparent conductors as described in U.S. Pat. No. 1,751,584, issued to Hansell. Later, in the 1950s, as disclosed in U.S. Pat. No. 2,825,260, issued to O""Brien, a plurality of transparent conductors, or filaments, were formed as long, thin rods, individually coated with an opaque material, and grouped into a bundle for transporting images. It was recognized that the size of the bundle of filaments depends upon the purpose for which the bundle would be used and that the cross-sectional size of the filament, in turn, depends upon the degree of resolution desired in the images. The fiber bundle was later refined as described in U.S. Pat. No. 3,016,785, issued to Kapany. This refinement included the use of flexible bundles and the use of motion in conjunction with a larger number of filaments each with a smaller diameter to further increase image resolution.
Over the past few years, fiber optic cables have been used in a growing number of applications to communicate information. In many of these applications, fiber optic cable has become a preferred medium of communication over standard metal cable because fiber optic cable has many advantages over metal cable. For example, operating at higher speeds and having a much greater bandwidth, fiber optic cable can carry more information than can metal cable. This information can span longer distances without being refreshed when communicated over fiber optic cable. Also, relative to metal cable, fiber optic cable has a greater resistance to electromagnetic noise and a much lower cost to maintain. Fiber optic cable further is much thinner and lighter than metal cable.
For example, fiber optic cables are used to transmit images in many modern imaging systems. These fiber optic cables typically comprise a fiber bundle with a large number of individual filaments. According to the traditional understanding in the art, the fiber bundle must have a large number of individual filaments, preferably maintained in relative position at both ends of the bundle, because the resolution of the transmitted images is substantially proportional to a number of filaments per unit cross-sectional area of the fiber bundle. Thus, image resolution increases as the number of filaments per unit cross-sectional area of the fiber bundle also increases. For the number of filaments per unit cross-sectional area of the fiber bundle to increase, however, a diameter of each filament must become smaller. Such filaments, due to their small diameters, have proven to be difficult and expensive to produce under current manufacturing processes. In use, filaments with small diameters also have proven to be fragile and have resulted in deterioration in image quality because of signal loss within individual filaments and crosstalk between filaments.
An illustrative imaging system is described in U.S. Pat. No. 5,208,891, issued to Prysner. Noting that optical images can be transmitted by fiber optic bundles, Prysner discloses a viewgraph projector that generates an optical image from a transparency slide and communicates the optical image via a multifiber coherent optical cable to a remote projection lens, which projects the optical image onto a screen. The viewgraph projector disclosed in Prysner therefore is in accordance with the traditional understanding in the art, communicating the optical image over a fiber bundle with a plurality of filaments. Similarly, the fiber optic intubating scope described in U.S. Pat. No. 5,363,838, issued to George, demonstrates the use of fiber optic bundles to illuminate a patient""s internal structures and to communicate images of those internal structures to an optical camera. The optical camera disclosed in George is disposed in a proximal end of a semi-malleable tube and, like the illumination source, requires power. The fiber optic bundles extend the length of the semi-malleable tube, and, when a distal end of the semi-malleable tube is a patient""s throat, the fiber optic bundles provide illumination for the optical camera and allow the optical camera to see the internal structures within the patient. Like the viewgraph projector in Prysner, the fiber optic intubating scope disclosed in George transmits images over a fiber optic cable comprising a fiber bundle with a plurality of filaments and follows the traditional understanding in the art.
Further, a recent article, entitled xe2x80x9cFiberoptic Tutorial,xe2x80x9d by Lee, describes the use of fiber bundles in fiber optic cables to transmit optical images. According to the Lee article, it is impossible for a single filament of a fiber optic cable to transmit an entire image. Stating that an individual filament can transmit only a spot with a certain color and intensity, the Lee article maintains, in accordance with the traditional understanding in the art, that a large number of individual filaments are required to transmit an image over a fiber optic cable. Further, as previously discussed, the Lee article requires that the individual filaments in the fiber bundle be aligned and fused together such that the individual filaments are ordered in exactly the same way at both ends of the fiber optic cable for the image to be created.
In view of the foregoing, it is believed that a need exists for a system for transmitting images that overcomes the aforementioned obstacles, limitations, and deficiencies of currently available imaging systems.
The present invention is directed toward a system for transmitting entire still and/or moving images via a single filament in a fiber optic cable. Through the use of the present invention, a camera produces an image, which is miniaturized and communicated in its entirety through a filament in a fiber optic cable to a display system. Upon receiving the image as miniaturized, the display system deminiaturizes and visibly presents the image substantially in real-time, and, being substantially continuously updated by the camera, the image can be presented as a moving image. The present invention therefore provides the advantages of visibly presenting real-time still and/or moving images of near and/or remote objects without requiring the use of either external power or fiber optic cables having a bundle of filaments.
A system of transmitting images in accordance with the present invention comprises a fiber optic cable, a camera, and a display system. The fiber optic cable has a filament for transmitting optical signals. Coupled with a proximal end region of the fiber optic cable, the camera comprises a lens system for receiving light signals from one or more still and/or moving objects. The lens system of the camera is optically coupled with, and in optical communication with, the filament of the fiber optic cable and is adapted to produce a substantially-reduced image of the objects preferably via an inverted microscope objective. Being focused on an initial image of the objects that is generated by the lens system, the inverted microscope objective is capable of intensifying and/or miniaturizing the initial image, thereby producing the substantially-reduced image. The substantially-reduced image, being substantially miniaturized, has a size that is substantially between one-thousandth and one-millionth of a size of the initial image.
The display system is coupled with a distal end region of the fiber optic cable and includes a lens system. The lens system of the display system is optically coupled with, and in optical communication with, the lens system of the camera via the filament of the fiber optic cable. Upon receiving the substantially-reduced image, the lens system of the display system is adapted to deminiaturize (or magnify) the substantially-reduced image, thereby producing a visibly-presentable image. The lens system of the display system preferably includes a microscope objective with a deminiaturization (or magnification) index that is substantially equal to an inverse or reciprocal of a miniaturization index of the inverted microscope objective. Using the substantially-reduced image as a object, the microscope objective is capable of generating a restored image with a size that is substantially between one thousand and one million times the size of the substantially-reduced image. Stated somewhat differently, the size of the restored image preferably is substantially equal to the size of the initial image produced by the lens system of the camera. The lens system of the display system is adapted to receive the restored image and, using the restored image as an object, is capable of generating and visibly presenting the visibly-presentable image.
In operation, a lens system of a camera is directed substantially toward one or more still and/or moving objects to be visibly presented. The objects reflect and/or otherwise emit light signals, some of which are directed substantially toward, and are received by, the lens system. The lens system of the camera generates an initial image of the objects and communicates the initial image to an inverted microscope objective. Being focused on the initial image, the inverted microscope objective intensifies the initial image, generating a substantially-reduced image of the objects. The substantially-reduced image is communicated in its entirety and in real-time from the lens system of the camera to a lens system of a display system via a filament of a fiber optic cable. A microscope objective included with the lens system of the display system receives and deminiaturizes the substantially-reduced image, producing a restored image of the substantially-reduced image. Being focused on the restored image, the lens system of the display system generates and visibly presents a visibly-presentable image of the objects.
It will be appreciated that a system for transmitting images in accordance with the present invention provides the capability of visibly presenting images of near and/or remote objects substantially in real-time. Also, since the lens system of the camera is capable of substantially continuously generating and intensifying images that can be substantially continuously transmitted to the display system via the fiber optic cable, the lens system of the display system is adapted to substantially continuously deminiaturize and visibly present the images. The image of the objects therefore is continuously updated and therefore can be visibly presented as a moving image. The system of the present invention provides the further advantage of communicating entire images through a single filament of a fiber optic cable without reducing image quality, thereby avoiding the need for and/or increased expense associated with fiber optic cables with a multitude of filaments. Since each filament in a fiber optic cable can be adapted to communicate entire images, the fiber optic cable can experience a substantial increase in its overall data transfer rate. Lastly, it will be appreciated that the system of the present invention provides the still further advantage of capturing and visibly presenting images without the need for a power source.